Major emphasis in the coming year will be on determining the toxicological and carcinogenic potential of the PCB metabolites. Detailed evaluations of the effect of the synthesized TCB-arene oxide and hydroxylated metabolites on isolated cell membranes, cell culture and bacterial systems will be conducted. In addition, we will continue to evaluate the specific nature of the association of these metabolites with cellular macromolecules and to relate these molecular changes with the toxic manifestations that are observed. We will also synthesize and evaluate arene oxide intermediates of other PCB compounds to determine their toxicity and capabilities of interacting with cellular macromolecules.